The present invention relates to disposable absorbent articles, such as diapers and the like.
A varied assortment of disposable absorbent articles have been proposed for use in receiving and retaining body fluids. Such articles, e.g., disposable diapers, sanitary napkins and the like, have normally been constructed with a fluid impervious backing sheet, a fluid pervious cover or top sheet, an absorbent pad intermediate the backing and cover sheets, such as comminuted wood pulp termed in the art as "fluff." Although increasingly popular due to disposability, certain problems remain associated with the absorbent pads which prevent the articles from being totally satisfactory.
First, it is necessary that the pads rapidly spread body fluids from the point of application toward remote locations of the pad in order to minimize pad saturation in localized areas and make maximum use of the full pad capacity. Second, it is desirable that the pad preferentially retains the body fluids at locations spaced from the cover sheet in order to minimize back wetting through the cover sheet with attendant discomfort to the wearer. Third, the pad should be soft and conformable to the shape of the wearer in order to provide a proper fit of the article and maximum comfort. Finally, the pad should be made in accordance with simplified manufacturing techniques in order to reduce the cost of the disposable article to the consumer.
It has been found that coatings of absorbent materials on the pad enhance the total amount of fluid capable of absorption by the absorbent article. These materials are the well-known suberabsorbing polymers of the acrylic type, such as the cross-linked poly aerylonitrile and the starch grafted poly acrylonitrile, as well as such products as described in U.S. Pat. Nos. 3,645,836, 3,932,322, 4,055,180, 4,055,184, 4,084,591, 4,090,013 and 4,333,461.
In my earlier filed application, Ser. No. 313,040, filed Oct. 19, 1981, there is disclosed a disposable absorbent article having a fluid impervious backing sheet and a fluid pervious top sheet, a pad assembly comprised of a loosely formed pad adjacent the cover sheet and a second pad between the first pad and the backing sheet and having compressed regions throughout at least a substantial part of the second pad. Such a pad is functionally superior to a conventional single pad-type disposable product.
In U.S. Pat. No. 3,612,055 there is disclosed a single pad diaper construction wherein the one surface not in contact with the top sheet is processed to form a paperlike skin to effect fluid spread to the back side of the diaper.